Up to 60,000 people reportedly gathered in the rain to demand fair elections.

The protest was officially authorised but dozens of people were arrested as they moved to other parts of the city, many outside President Vladimir Putin's offices in the city centre.

Unauthorised rallies on the last two Saturdays saw hundreds detained. This is the fifth demonstration in a month.

Many Muscovites are unhappy that opposition candidates have been banned from running in municipal elections in September, but anger has increased after apparent incidences of police brutality in previous weeks.